


Addiction

by Celestialviperz



Category: Teenage Mutant Ninja Turtles (TV 2012)
Genre: Blood Kink, Dark Fantasy, Eventual Smut, F/M, Family Secrets, Friends to Lovers, Hurt/Comfort, Implied/Referenced Child Abuse, Murder Mystery, Secret Relationship, Slow Burn, Vampires, donnie is obsessed, karai likes to push buttons, leo dosen't like killing, reluctant killing, this familiy is falling apart, will get very gory in later chapters
Language: English
Status: In-Progress
Published: 2018-08-15
Updated: 2018-10-01
Packaged: 2019-06-27 17:56:15
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 5,149
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15690450
Author URL: https://archiveofourown.org/users/Celestialviperz/pseuds/Celestialviperz
Summary: Leo had long become accustomed to his vampirism, however over the past month he found himself losing control more and more. Now, with Donnie unknowingly hot on his tail searching for a killer, and Karai getting a tad too involved, Leo struggles with keeping everyone from finding out the truth and dealing with the moral conflict of his actions.





	1. Chapter 1

Leonardo stood alone out on a rooftop, far off any patrol route he usually took with his brothers, they were the last people he wanted to run into right now. An argument with Raph had spiraled out of hand, long story short, everyone was mad at him for their own special reason. He dragged himself to the ledge and sat on the cool stone, his legs dangling off the edge. The city seemed dead, as though the world had stopped turning and time no longer mattered, not even a breeze existed here, it filled him with a euphoric sense of freedom. Admittedly he had probably been extremely irresponsible, no phone, no weapon, just him, not his smartest move but he had been angry and desperate to get out, away from everyone. It wasn’t the first time he had been here, lower Manhattan wasn’t a regular visit for them, they can’t cover everywhere so here and east village got left to the Mutanimals, luckily this meant it was the last place anyone would look for him. Things had been getting bad lately, his temper had been short for the past week, needless to say, it had been causing some issues at home. It wasn’t a mystery why it was happening, he knew he had left it too long, but he couldn’t help it, he hated this, everything about it.

  
Obnoxious laughter caught his ear, crossing the road below him was young woman, clearly drunk, waving to her over very drunk friends walking the opposite direction. The click of her uneven steps echoed as she stumbled down the empty street. She turned at the sound of clattering behind her, not a soul in sight simply an empty cider bottle rolling along the pavement. Her eyes lazily followed the bottle as it fell from the curb onto the road, satisfied she turned back around only to be face to face with a green creature not even a foot away. A sharp inhale was all that escaped her before she was left paralyzed, wide eyed and gasping for air, she couldn’t even call for help before his teeth sunk into her neck, her hot pink nails digging into his skin as he greedily drank every drop of blood from her body. His heart was racing, the heavenly, bittersweet flavor of human blood flooded his senses and suddenly he could no longer control himself, he needed more, the girl had long since gone limp, yet he continued to drain all that was left of her. Leo finally dragged his fangs from her neck, panting for breath as he pulled away, the poor girl was white as a sheet making the deep crimson wound all the more attractive. Laying her down behind a bin in the alley he grimaced, the thought alone of what he had done to this girl made him sick to his stomach, still instinct betrayed him, his eyes where dilated and his breathing erratic, he craved more, it disgusted him. Leo Cleaned himself up and slowly began walking home, unable to bare looking at the girl a moment longer, but her face plagued his mind, hollow brown eyes with tear smudged mascara running down her cheeks, the candy red lipstick slightly smudged, probably from some boy she had met, some boy she would never meet again. He realized he had been standing above the manhole cover for some time now lost in his thoughts, he continued to stand there for a while more before managing to compose himself enough to continue home.

  
He ignored everyone when he got back, all the angry inquisitions as to where he’s been and if he knew how stupid he had been, despite their yelling, he impassively walked to his room and locked the door, resting his forehead on the smooth metal he could hear them outside voicing their disapproval, he didn’t care, why should he, come tomorrow they will have dropped it entirely, everything will be normal again. Leo busied himself with little things around his room, tidying discarded items laying adorned about the floor, trimming the small bonsai tree atop his drawers, replacing and lighting the candles, basking in the subtle pine aroma that enriched the room. He occupied his mind with these tasks, anything to not think about what happened, settling himself on his bed leo began reading one of a great many books he had, he needed something slightly more occupying than a comic book right now. Hours ticked by and slowly the candles started melting into little stumps as he drew near the end of another book.

  
Everyone would be waking up soon, first Mikey who would inevitably sit for an hour watching cartoons, then Donnie would shuffle to the kitchen to make coffee looking more like he belongs in a zombie movie than a kitchen environment. It was at this time that Leo liked to walk in, he didn’t sleep, or at least he hadn’t in a long while, regardless he liked to keep up appearances, he had always gotten up before Raph yet after Mikey so after the incident he continued ‘getting up’ at roughly the same time. As predicted yesterdays events seemed of little importance, his brothers more interested in their eggs and bacon than starting up pointless arguments. Leo smiles weakly at his youngest brother who places a plate of fluffy, white scrambled eggs and crisp bacon before him. It smells divine, he used to love Mikey's egg breakfast, he used to love a lot of things, now it just tastes bland and sickly as he forces himself to eat mouthful after mouthful knowing full well he’ll throw it up not long from now. Breakfast, despite being hosted at 3 in the afternoon, was never chipper, luckily Mikey was usually boisterous enough for the four of them as they ate. Today however the news caught Donnie's attention which brought a screeching halt to Mikey's latest tale as he was angrily hushed.

  
“…in just the past month, the young lady was found by shop owner Mia French early this morning, police aren’t releasing information on this case to the public at this time but urge people to be cautious when out late and recommend…” the news reporter drawled on as groups of people huddled around police tape sectioning off an alleyway.

  
“That’s the fifth one this month” Donnie stated pointing to the tv, “there’s something going on in lower Manhattan, these have gone from random killings to serial murders”  
Donnie had brought up the issue earlier in the month, Raph assured him the Mutanimals could control it and now that they hadn’t Donnie was rightfully agitated, frankly this was something Leo would rather try and stay out of, investigating himself is an issue he could do without, thus, he sat stabbing at his eggs, letting the scene play out.

  
“Donnie, I don’t like it either, but we have a hard-enough time dealing with the area we got, we can’t handle taking on a whole other part of the city.” Raph's tone was calm, he wasn’t angry at Don in fact they were on the same page, but he was right, they couldn’t handle patrolling more city, not with the increased activity at least.

  
“I know that, but we can’t just do nothing”

  
“idea!” Mikey chimed, spinning round on his heals to face them, “how’s about we trade the Mutanimals one of our patrol areas while we sort out all this whacky nonsense in lower Manhattan.” A proud grin spread across his face as his brothers stared sceptically up at him.

  
“y’know, you can be smart when you wanna be” Raph stood placing a hand on Mikey's shoulder, “how’s that sound to ya fearless” eyes suddenly on him, he put on a smile and played the part

  
“As long as we’re saving people, I don’t see how it can be an issue” it was like he was losing at chess, his opponent now had him in check, one wrong move and he’s in checkmate.

  
As his brothers started making plans for switching up the patrol areas Leo excused himself to the bathroom. He was shaking, not because he had just thrown up a perfectly good egg breakfast. He didn’t know what he was going to do next, sure he could just up and move to a different part of the city, but wouldn’t that look suspicious, yet if he stayed where he was he risked his brothers finding him. He sighed looking back at his own tired reflection, just last month he had been fine, sustaining himself on animal blood, yes it tasted worse and was far less filling, but it was better than the alternative.

  
At Raph's call he quickly washed his hands and walked to the dojo, training was usually one of the few stress-free things that they did, it worked well as everyone got to vent themselves in a safe environment, a time where they all seemed at ease and enjoying each other’s company for once. Times like these reminded him why he loved his family so much, despite the bickering and disagreements everyone cared for one another, the facetious banter and friendly competitiveness that brought them together showed that much. They where set up against one another, Raph facing off with a somewhat worried looking Mikey, leaving himself squaring up with Donnie, the two spent a good while dodging blows and countering attacks, after years of training against each other they all understood their fighting styles fairly well, it became easy to pick up small details, little giveaways on their next move which resulted in landing hits become quite of a struggle. Regardless of this, the novelty of sparring with his brothers never seemed to wear thin.  
The light in the dojo was always distracting, the rays of sun that crept down were an inconvenience at best, even though they could hardly be considered harsh. Leo's eyes stained against the light which only encouraged the throbbing in the back of his head. Unconsciously he allowed his mind to become distracted, focusing too much on the hindering sunlight, a sudden sharp sting in his shoulder broke him out of his reverie, before he could comprehend what had happened his feet flew from under him as he landed harshly on his shell.

  
“you ok Leo?” Donnie towered over him, his frame blocking the light that shone down, his features resembling both shock and worry, “I didn’t mean to take you down so hard, kinda thought you’d dodge” he apologized as Leo took his offering hand, dragging himself off the floor.

  
“don’t sweat it Don, I just got distracted, good fight” he reassured his brother with a smile, sheathing his weapon, though it did little to ease his expression.  
Leo turned to his attention to his still fighting siblings, attempting to ignore the uneasy feeling of eyes watching him, Raph had Mikey uncomfortably pinned, sneering triumphantly at the helpless turtle crying mercy beneath him

  
“yame” Splinter snapped, stopping to the quickly devolving fight

  
The boys lined up before him and listened to yet another long drawn out lecture on how training was extremely important and even though you know your opponent always expect the unexpected, don’t be predictable, things they had heard countless times. After being dismissed they all went their separate ways, the predictability of his family was almost laughable, though he could hardly talk.

  
“hey Leo, could I see you for a second?” Leo tensed slightly, it was a harmless question, yet Donatello’s unreadable expression filled him with unease.

  
Simply nodding Leo followed his taller brother to the lab, a sickening anxiety filling his stomach and tightening around his chest, he didn’t know what he was afraid of, even though worst case scenarios flurried round his head, they where nothing to be concerned over. The large lab doors slid shut echoing through the room, Donnie turned to his brother, but said nothing, a heavy silence hung in the air as the two stood staring at one another, Donnie shifting awkwardly on his feet.

  
“Are you ok?” Donnie eventually asked, seemingly repeating his question from before

  
“Donnie, I said its fine, you didn’t hit—”

  
“not your shoulder, I mean are you alright, you’ve been acting… off lately” he clarified, sharply cutting off Leo mid-sentence, playing awkwardly with his own hands  
Leo cursed internally, he thought he had been playing things off well, then again of course Donnie would notice, as absent as he was through the day, Donatello was rather observant, perhaps something he picked up from April.

  
“everything’s fine, you and Raph aren’t the only ones strung up about these killings you know” a lesson he had learned from Karai, the best way to lie, is to use the truth.  
“Yeah, right… sorry, I was just worried what with your temper and yesterday’s events and all”

  
“you’ve got nothing to worry about” Leo smiled honestly, the gesture seemingly calming his brother down, his eyes flicked to his bench as he began backing towards it  
“uh, Raph was planning on going to the Mutanimals later, y'know to talk about the patrol, maybe you should go too, so you can plan the routs we’ll be taking” taking the hint that this conversation was over, Leo agreed and took his leave.

  
Dusk rolled around and Leo found himself leaning against a small desk in a room full of mutants, he had gone with Raph as suggested, something the hothead hadn’t been keen on but agreed with. Discussing the switch hadn’t taken long, slash agreed that the situation would be better left to them, now with the patrol routs sorted and everything sealed with a handshake, the group where laughing boorishly, reminiscing fights they had had not long ago. Personally, it wasn’t his scene, though he could see where Raph found interest in it, the only thing missing was Casey. Deciding to take his leave, Leo slipped out.

  
He strode from roof top to roof top trying his best to ignore the dull stinging that was painfully radiating all over his body, the sun rested low in the sky, only just visible over the horizon, even still it affected him horribly, he squeezed his eyes shut, trying to fight the oncoming migraine, though it did little to help. A sudden sense of being watched overcame him, his eyes darted around in an attempt to find, anything,

  
“hey stranger, where’ve you been hiding” a mischievous voice called from the shadows, Leo couldn’t help but roll his eyes

  
“I should be asking you that” he called out, still unable to find her in the tall shadows. The two hadn’t really seen much of each other over the past few months, despite the rapid increase in foot activity Karai was never anywhere to be found,

  
“been busy, though, it’s been boring.” Leo grew nervous as her voice moved, his hand instinctively shifting to his katana, “I thought maybe we could have some fun”

  
Instantly their swords where locked, a split-second reaction as she jumped from behind, a devilish smile and a playful glint in her eye. Pushing each other back they began their deadly dance, the high ringing of metal clashing as they chased one another across the rooftops, parrying attacks, fighting for the upper hand

  
“what’s up, you gone soft” she teased delivering a swift kick to his leg, falling to his knee he rolled quickly away from her blade,

  
“you kidding?” he grinned, unsheathing his second katana “I was going easy on you”

  
They continued their dance, the sun now long since gone, but neither cared as slowly they exchanged cuts and bruises, their endurance wearing thin. It was a rash move, she brought her tanto down without thinking and before she knew it her blade was halfway across the roof, now Leo had her pinned at the ledge, two katanas pressed to her throat, but she had a dagger to his, thus leaving them at a standstill.

  
“looks like I win this one”

  
She simply sneered, not gracing him with an actual response. Before he could boast on his triumph more, Leo noticed his hands trembling slightly around the grip on his swords, he hadn’t realised how hungry he was until now, when he was so tantalisingly close he could practically taste her blood pumping through her veins. Abruptly, he pushed himself away, stumbling as far across the roof as he could, he faintly heard the clatter of his katana hitting the floor but he was far too caught up in trying to calm himself to care, the corners of his vision where dark and blurry, drums where pounding in his head and he could hardly breath, he needed food, anything, something. A hand rested on his shoulder, he spun, losing his balance as he did so, Karai's brow was furrowed, her eyes scanning him as he wobbled,

  
“s-stay away from me!” it was more of a plea than anything, he kept his arm outstretched as he backed away, Karai looking utterly lost in the situation

  
“the hells gotten into you?” he didn’t answer, simply taking the moment to sprint off as far from Karai as he could get, leaving her speechless on the roof trying to figure out what had just transpired.

  
After quickly putting as much distance between himself and Karai as was possible in his current unhinged state, he scoured for something to sate his hunger, becoming more maddeningly desperate as his thoughts became more incoherent and instinct started taking hold. Blood lust fuelled tunnel vision controlled him, cognitive thought supressed by the primal need for blood, driving him towards what was now his current prey. With the darkness as his cover he swiftly subdued his target, falling into the deep embrace of blissful sensation, a feeling that began fading far too fast for his liking as he shot upright with some disdain, straddling the now dead purple dragon, tentatively caressing the wound with trembling hands, lowering to cautiously lap up the blood that coloured the punctured neck sending a cool shiver down his spine.  
Vibrating in his pocket dragged him from his trance of consuming every drop of blood physically possible, his phones way of informing him that he would have to meet up for patrol soon. With the cloud slowly lifting from his mind he became overly aware of his situation, leaping off the newly made corpse, horror tightly binding his lungs. Purple dragon or not he had just killed someone, again, throwing his head into a flurry as the knowledge that he was losing control of the situation hit him rather abruptly. This was one of those things that Leo couldn’t exactly get advice on leaving him stranded to just figure it out.

  
With time not being something Leo had the grand luxury of, he forced himself to some form of composure, realising his blades lay somewhere in the direction of ‘with Karai’, forming yet another pit in his stomach as he thought of how she may well have taken them and had them reformed into twenty small daggers with which to stab him. Despite having little faith that his katanas weren’t in the melting process, Leo began heading in the vague direction of where he came from, upon finding, much to his surprise, that his katana leaned neatly on an air duct alongside a small note written in a fine, cursive font,

  
‘careful goodie boy, next time I might keep them ;) ~K’

  
He couldn’t help but smile, folding the scrap into his belt as he hurriedly made his way to the meet up point to begin patrol.


	2. Chapter 2

Despite the steep increase in foot activity and the current murder spree, the night was painfully uneventful, consisting only of a single scruff with the Kraang that was about as momentous as a bar fight but with none of the fun. The overall lack of activity had left everyone slightly dissatisfied and as a result, agitated, both at this patrol being a bust and Mikey, mostly Mikey. With nothing to do he had resolved to making his own entertainment at the expense of Raphs temper, Leo sighed knowing that they would have to head back soon or his little brother was going to end up hurt again and he was running out of excuses to give sensei to cover Raphs shell.

Senseless squabbling aside, staying out any longer seemed redundant as there wasn’t anything to do and no one was in a good mood, that and Leo half hoped that maybe inviting April over would cheer up Donnie. He had started out the night so optimistic, unfortunately as they drawled on and anything relating to the murders or just plain entertainment made no appearance, Donnie’s demeanor had gradually dropped. Looking back, his downtrodden brother was completely defeated and disinterested in his surroundings. It hurt, seeing him so upset, however the guilt Leo felt dwelt not in his chest but inside his brain. What he had done he could not un-do. He could try to make amends in subtle ways, but a confession was out of the question, even to his brothers. Only in the quiet of his room could he mull over the crimes he had committed, battling with his own mind in efforts to convince himself that he wasn’t a bad person, really. Leo’s eyes fell to the floor, he didn't feel like he deserved the love of his family and friends, but he clung to it and hung the shreds of his sanity on it. He hoped and wished that someday it would all disappear, like a lifting fog, and everything would be fine, though within him he knew that he would never be free from this sin, and the guilt would stay with him like an ugly scar.

Leo quickly became lost in the murky sea his mind, drowning in emotion that clouded his judgement, coloured by his actions. Over the past month he had been losing control over himself more, his cravings and desires had become irresistibly strong, painfully reminiscent of when he first awoke on a cold construction building floor feeling like the training dummy in the living room. Leo soon found himself not fully in control of his own actions, quickly leading to the murder of three teens that he vividly remembers as a fever dream of blood and screams. Luckily the news had been happy to help in filling any holes in his memory and peaking Donnie’s interest, he had been obsessed ever since, even as the deaths dwindled, and the news stations moved on, Donatello was like a fanatic with his corkboard and yarn all over the map with pictures and news clippings. Truthfully Leo had little idea whether his brother’s obsession stemmed from desperately wanting to catch a killer of from wanting to prove or disprove the vampire theory, all he knew was that he had evidently caused his brother to be all but devoted to finding someone two feet in front of him and couldn’t help but worry that it would eventually tear a rift in his family.

Mikey’s cries of pain brought his mind back to reality, it was only a matter of time before Raph reached the end of his tether and began twisting his little brother into a pretzel. Letting out a sigh of resentment Leo stared at the scene before him, not surprised in the slightest.

“Raph” his voice low and warning, if there was one thing he could go without tonight it was bickering.

At the call of his name Raph looked up, his eyes locking with the unimpressed gaze of his older brother, a gaze that looked almost condescending.

“Tell him!” he protested, further tightening his grip on Mikey's leg to emphasize, “he’s doing it on purpose what do ya expect me to do”

“show a bit of self-control maybe?”

“Raph? Self-control? You’d have more luck playing charades with a blind man” Donnie dryly remarked, his tone lacking in his classic sassy attitude yet skipping none of the sarcasm.

Raphs fierce gaze shifted to their apathetic brother, a storm clearly brewing between the two, Leo wasn’t sure weather to jump in now or let it play out as the two stared one another down, Donnie’s eyes all but daring Raph to start an argument. Air between the two hadn’t been great, what with Donnie obsessing over the murders, it was safe to assume that to an outside observer he was becoming a bit ‘Leo’ about the whole ordeal which came with the added bonus of Raph not being fond of either of the two.

“listen, just cause you’re upset we didn’t find any leads on your precious murder case don’t mean you gotta go getting all smart mouthed.” Raph released his hold on Mikey, squaring up with Donatello

“us not finding anything has nothing to do with this, your incessant whining on the other hand” the situation was quickly elevating, Leo realized he had to step in soon lest this devolve into a fist fight.

Raph was clearly on the brink, his temper was on a hair-trigger. The smallest thing would have him flying into a rage, yelling, saliva spitting out with each jagged word.

“I think its about time we headed home” Leos voice was steady and commanding as he slowly approached the two in attempts to diffuse the situation.

Both brothers seemed to take no notice, continuing the tense standoff. Leo was prepared to jump in if either decided to throw a punch, his eyes flicking anxiously between the two.

“yeah, a plan I can get behind” Raph huffed, his glare lingering on Donnie as he made for the roof edge, dropping out of sight. A sigh of relief escaped him as his body relaxed, he hadn’t realized how tense he had been.

The others had given Raph some time to get ahead before following. The trip home was silent, much to Leo’s relief Mikey seemed to have some sense to keep his mouth shut for a while. Splinter hadn’t been too pleased when they got back, questioning why Raph had gotten home first and seemed angry, both Mikey and Donnie had quickly scattered off to their respective lab and bedroom leaving Leo to fathom up some half assed excuse about a disagreement on the way home, skipping as best he could on the details. Eventually being allowed to go to bed he swiftly made for his room, gently closing the door behind him, relief flooding him as the metal latch quietly clicked. In the sanctuary of his room he had a brief reprieve from the outside world. Though he was never without constant reminder of said outside world, to his right was the gentle thumping that was without rhythm as Raph vented his anger on presumably the far wall of his room. While to his left sounded the chipper techno music resonating from whatever gaming device Mikey was entertaining himself with. 

Regardless the faint noises failed to distract him, he was in his own safe space where nothing could affect him, with this he made himself busy lighting candles and selecting a good book. Sitting against his bed, he reached under pulling out a smallish Styrofoam box covered in tape, peeling it open revealed a few ice packs surrounding a stockpile of red gelatinous cubes. He learned after a bit of internet browsing that there was a grocery store in china town that sold animal blood in cubes much to his convenience. He sat flicking through the pages of his book occasionally popping a blood cube in his mouth, the chill metallic taste was harshly bitter on his pallet, it had had never tasted fantastic yet now it was near depressing compared to the sweet nectar that pumped through the veins of people, the way it felt as the taste seemingly engulfed him was heavenly, but this was the better, though it may be bland.

Across the hours he had been sat, Leo hadn’t actually read any of the book he had sat down to read, his mind was caught up thinking on tonight’s events with Karai, he hated how close he had come to losing control, outside of April and Casey she was the closest thing he had to a friend, there was a mutual understanding between the two, friendly sparring and banter, an appreciation for fighting styles and swords. Occasionally they provided an ear to listen, but things never got mushy, no cutesy heart to hearts, just a growing friendship, he liked it. Once they sat on a roof in the center of town during a festival and people watched, Karai seemed to enjoy mocking the outfits of passersby and Leo enjoyed her menacing quips, she had a unique type of humour. Tonight’s events worried him profusely, he dreaded to think what would happen if he hurt Karai, could he turn her? Or what if he just killed her? Either way what does she think of him now, after his freak out she must think he’s off the plot. His mind kept drifting to that moment, inches from her face with his sword against her neck, veins faintly visible through her pale skin, thrumming in time with her sporadic heartbeat. He struggled to find the words to describe the scent, words hardly did it justice, one could say he could almost feel it. The shape of her blood, the texture of it, the consistency, the taste, the movement of it in her veins all manifesting itself in a single smell. Fragrance was far too similar to ‘perfume’, false, contrived, chemical. Flavour would be a better word. A flavour so strong that it racked his entire body, consumed him and made his head spin.

Leo snapped his head round to look at his door, faint clicking followed by gentle, barely audible sound of sneaking footsteps sounded just outside his room. Obviously, someone was sneaking out, had his hearing not been as good as It was he wouldn’t have been any the wiser to the sly goings on beyond his door. Sliding the box back under his bed, he rose from the floor and glided to the door in one swift movement, he paused, it occurred to him that he had just been eating and running out after one of his brothers looking like the reanimated corpse of what he once was probably wasn’t a great idea. Slowly backing towards his bed Leo ran his tongue over his teeth, allowing the sharp protrusions to graze his it as he did so. Maybe tonight it was better to just leave whoever it was to do their own thing, he had to have some faith his brothers wouldn’t get into too much trouble without help, besides, it was likely just Raph going over to Casey’s to vent like he usually does. Lowering himself back to the floor Leo restarted his book, letting the candles dwindle around him until breakfast.

**Notes for the Chapter:**

> just a bit of depth building, things should hopefully pick up next chapter, sorry :(


End file.
